How it works - Getting the fantastic space photos - ESO's VLT (Very Large Telescope)

In principle, the larger a telescope’s mirror, the finer the details it can see. Continuing to increase the size of telescope mirrors is not an easy task, so astronomers have come up with a new technology to see even finer details: interferometry. This observational technique combines the light received by two or more telescopes and allows them to act as a single unit with a mirror diameter equivalent to the distance between the telescopes. Engineers designed the VLT so that it can also be used as an interferometer. Along with the four 8.2-metre Unit Telescopes, four mobile 1.8-metre Auxiliary Telescopes (ATs) were included in the overall VLT concept to form the Very Large Telescope Interferometer (VLTI). The ATs can move between 30 different stations, and at present, the telescopes can form groups of two or three for interferometry. Credit: Visual design and editing: Martin Kornmesser and Luis Calçada. Cinematography: Peter Rixner. Editing: Herbert Zodet. Web and technical support: Lars Holm Nielsen and Raquel Yumi Shida. Written by: Herbert Zodet, Henri Boffin and Adam Hadhazy. Host: Dr. J. Narration: Gaitee Hussain. Music: John Dyson from the CD darklight. Footage and photos: ESO. Directed by: Herbert Zodet. Executive producer: Lars Lindberg Christensen.